Seat spring



March 4, 1941. c. H. GRAHAM `SEAT SPRING Filed April 17, '1959 2 'sheets-sheet 1 l Patented Mar. 4, 1941' UNITED STATES SEAT SPRING Clare ll. Graham, Detroit, Mich., asslgnor to General Motors Corporation, Detroit, Mich., a corporation ot Delaware Application April 17, 1939, Serial N0. 268,159

Z Claims.

This invention relates to seat springs and particularly seat back springs. In seat back springs. at the present time, it is customary to use a so called spacing strip between the outer coils of the springs. These spacing strips are intended to hold the trimming material from being pressed or falling in between the coil springs.

It has been customary to use burlap strips for this purpose but, in order to give the springs what has been thought to be the necessary freedom of action, it has been customary to use long coil springs in the edges of the burlap and the burlap has been loosely shirred on these coil springs so as to give the spacing strips a longitudinal yield. It has also been thought necessary to make the spacing strips slightly wider than the distance between the tops of the coil springs so as to give some yield in this direction.

The present invention is an improvement over this arrangement in eliminating the long coil springs and therefore making for economy. This is achieved by using short coil springs at each end of the strip for connecting the strip ends to the end rows of coil springs. It has been found that this acts equally well and is very much cheaper to build by reason of eliminating the long coil springs.

In the drawings:

Fig. 1 is a plan view of a seat back spring equipped with my improvement.

Fig. 2 is a top or edge view of the spring shown in Fig. i.

I .lFig 3 is a cross section on the line 8 3 of g. v v

Fig. 4 is a fragmentary pian view showing a modified form. i

Fig. 5 is afragmentaryviewof anothermodiiied form of construction.

The spring seat is provided with the usual border frames I and l. .'lhe top and bottom border frames are connected by the hinging diagonals I.

I. No claim is made to this much of the construction as it is old and conventional. The burlap spacing strip is designated l and this is clipped to the top coils of two adjoining rows of springs by hog rings 1. The burlap `strip is folded back on the edges to form a hem as at l. Preferably. the strip is stretched taut as shown in Fig. 3. At each end of the strip, the material is folded over (as shown in Fig. 2) at I, forming a Iloop and through this loop is threaded a small coilspring Il whoeeendshookovertheendrow ss oithehour-glssstyveofm'ingl. Ibispermlts The rear ends of the hour-glass type of springs 4 are supported by the cross members the entire strip to yield longitudinally when the load is on the strip and the adjoining springs. I find that this gives all the freedom of action that is necessary and is much cheaper than a spacing strip designed to yield intermediate its length 5 and which has the loose burlap shirred upon small coiled springs that run the entire length of the strip.

In a. seat back spring of normal height, there will ordinarily be four rows of springs and three 10 of my improved spacing strips will be used. But,

I 11nd that, if it is desired to add more flexibility where the greatest load comes, two spacing strips can be used between the top and bottom rows of springs and crossed coiled wire springs Il can be 15 used as spacers for the center rows of springs. This modiiled form is shown in Fig. 4 of the drawings.

Preferably, coil connecting springs i2 are used between the individual springs of the top row in 20 order to prevent the trimming dropping through these springs at the point where it is curved backwardly. A top spacing strip Il connects the top coil springs with the top border wire I4.

In Fig. 5, a modified form oi construction is 25 shown in which, in place of the hem l with the coil spring Il, separate coil springs Il are hooked in the corners of the burlap spacing strip I and Valso hooked over the top coils of the end springs. What I claim is: 30

l. In a seat spring. the combination of border frames, one of the border frames provided with cross members, springs anchored at one end to the cross members andspacing strips of ilegible material connecting the springs together at the g5 other ends. the said spacing strips being connectedtotheendspringsoftheassemblyby'a yieldabie member. the said connection being in theformoi'aloopofthematerialofthespacing stripateachendandasmallcoilmringthresded so'. through the loop and connected at-each endy to springs in the end row of springs. ,v f

2. In a seat spring. the combination of frames and coil springs supported by one of the frames and having their opposite ends connecdwml the other border frame, flexible spacing strips having loops .in their ends for tying the said ends of the springs to each other.v the said spacing strips comprising fabric strips connecting adiacent springs in substantially taut relation. and 50 yieidable means connecting the endsoi the taut spacing strips to the end rows o! coil springs in the form of small coil springs threaded through loops in the ends of the spacing strips.

CLARE H. GRAHAM. u 

